File with less than 100 rows causes corruption

```
Following the sample on the homepage, the file created came out as corrupted. 
After a few trials, I found that the issue occurs when there are less than 100 
rows with added cells. A workaround is to add X additional rows with a blank 
cell if the number rows is less than 100.
```

Original issue reported on code.google.com by `leandro....@gmail.com` on 20 Mar 2014 at 3:53
